Rescue is still underway for the 13 workers trapped in a tunnel that collapsed Sunday night in southwest China's Guizhou Province.
Rescuers say they will implement a three-stage plan to rescue the workers who are trapped 600 meters deep in the tunnel near Shiqian County.
Luo Qiang is a deputy director of the provincial transport department.
"The first step is to drill an 11-cm horizontal bore to provide oxygen for the trapped workers. The second step is to drill a pilot tunnel with a cross section of four square meters in the middle of the right side of the collapsed section. The third step is to drill a four-meter-long inclined pilot tunnel near the exit."
The trapped workers have received several mobile phones and sent out letters through a narrow opening.